Aminoglycoside antibiotics (AGAs) are widely used in the treatment of a variety of refractory bacterial infections. The most important side effects and therapeutic limitations of AGAs are inner ear damage (ototoxicity) which can produce irreversible hearing loss and kidney damage (nephrotoxicity) which can lead to kidney failure. Prevention of AGA-induced ototoxicity and nephrotoxicity has been a major therapeutic objective in biomedical research. One major goal at the laboratory of Dr. Julian Simon is to identify the biological target of the otoprotective PROTO1 analogs (PROTO) to determine their mechanism of action in preventing AGA-induced inner ear hair cell death. To achieve this goal, the laboratory recently identified several candidate PROTO targets in zebrafish through photoaffinity pulldowns coupled with mass spectrometry. In this fellowship proposal, the three specific aims are designed to test the hypothesis that one of these mass spectrometry- identified PROTO candidate targets plays a critical role in controlling hair cell death and surviva in response to AGAs: 1) Validation of the interactions between PROTO and the most promising mass spectrometry-identified candidate targets using western blotting and competition pulldowns; 2) kinetic analysis of interactions between PROTO and its targets using a surface plasmon resonance (SPR) biosensor; 3) investigation of the effects of the PROTO targets on AGA-induced hair cell toxicity using mammalian cell lines and conditional knockout mice. Identification of the biological PROTO target is expected to advance the understanding of the cellular pathways that regulate hair cell death and survival and promote the development of new therapeutic strategies to prevent hearing and balance disorders. The fellowship proposal will provide an invaluable hands-on experience and comprehensive knowledge in hearing protection research and preclinical drug development paving a solid foundation towards an independent research career as an investigator/scientist in the field of auditory and biomedical research.